The present invention relates, to electromagnetic wave absorbers made of magnetic ferrite materials and to a method of preparing the same. More specifically, the present invention relates to electromagnetic wave absorbers comprising a sintered ferrite material and a CuO--Fe.sub.2 O.sub.3 spinel-structured material, wherein the amount of CuO present in the CuO--Fe.sub.2 O.sub.3 spinel-structured material is from about 40 to about 60 mol % based on the total amount of CuO--Fe.sub.2 O.sub.3 material.